Heat exchanger



Jan. 7, 1958 I R. H. PEARSE, R, ET AL 2,819,045

HEAT EXCHANGER A Filed Dec. 4, 1953 4 Sheets-Sheet 1 Pig. 1 5 a c 1 4 130 g) Z4 q:j 56

V6 /6 1e Is I INVENTORS' RICHARD H. PEARSEJR ALAN c. BUTT ATTORNEYS Jan-7, 1958 R. H. PEARSE, JR, ET AL I 2,819,045

HEAT EXCHANGER Filed Dec. 4, 1953 4 Sheets-Sheet 2 56 Fig. 2.

/0 INVENTORS RICHARD H. PEARSE, JR. ALAN G. BUTT- :444, f flaw ATTORNEYSJan. 7, 1958 v R. H. PEARSE, JR., ET AL 2,819,045

' HEAT EXCHANGER Filed Dec. 4, 1953 4 Sheets-Shed 5 IN VEN TORS 0RICHARD H. PEARSEJR ALAN G. BUTT ATTORNEYS WOM O OM Q9 09 Q Q @400 040 0Jan. 7, 1958 Filed Dec. 4, 1953 A- Fig. 6.

United States Patent Oflice 21,819,045 Patented Jan. 7, 1958 HEATEXCHANGER Richard Henry Pearse, Jr., and Alan George Butt, La Crosse,Wis., assignors to The Trane Company, La Crosse, Wis.

Application December 4, 1953, Serial No. 396,125

2 Claims. (Cl. 257-241) This invention relates to heat exchangers andparticularly to heat exchangers for cooling the oil and heating the fuelof an engine.

The passageway for one of the fluids is formed by a series of flatplates which require the fluid to flow in a tortuous path of greatlength.

The other fluid is conducted throughthe heat exchanger by a plurality ofseparate passageways in the form of tubes so that each tube may receiveand discharge a metered quantity of fluid.

A general object of this invention is the provision of a very efficientheat exchanger that is simple to construct, inexpensive to manufactureand strong and durable in use.

Another object of the invention is to provide a heat exchanger Which canbe made by assembling simple structural elements and brazing or weldingthem to form an integral structure.

It is another object of this invention to provide a blockoff tube insideof each tubular passageway to increase the velocity of flow and toincrease the amount of prime surface.

Other objects and advantages of the invention will be clearly apparentas the specification proceeds to describe the invention with referenceto the accompanying drawings, in which- Fig. 1 is a plan view of theheat exchanger of this invention.

Fig. 2 is a side view partly in section to show the interiorconstruction.

Fig. 3 is an end view of the improved heat exchanger.

Fig. 4 is a sectional view taken on line 4--4 of Fig. 1.

Fig. 5 is a sectional view taken on line 5--5 of Fig. 1.

Fig. 6 is a sectional view taken on line 6-6 of Fig. 4.

Fig. 7 is a plan view of a fin of one series.

Fig. 8 is a plan view of a fin of a second series.

Fig. 9 is a fragmentary sectional view of a portion of the fins taken onthe line 99 of Fig. 7.

Fig. 10 is a diagrammatic view showing a portion of the path of fluidflow through the heat exchanger.

Referring to Figs. 13, numerals 10 and 12 designate the tube sheets ofthe exchanger. A plurality of fins 13 and 14 lie between the tube sheets10 and 12 and are fastened to each other and to the tube sheets byclosure strips 16.

Two manifolds 18 are brazed to the tube sheet 10, and to the fins 13 and14, and to the closure strips 16 which the manifolds 18 overlie. Twomanifolds 20 are similarly brazed to the tube sheet 12 and to the fins13 and 14 and to the closure strips 16 which the manifolds 20 overlie.

Manifolds 18 and 20 have openings 22 and 24 respectively which areadapted to be connected to fluid supply and discharge conduitsrespectively. For purposes of de scription it will be assumed thatopenings 22 are connected to fluid supply conduits and openings 24 areconnected to fluid discharge conduits. It should be understood that theflow may be in the opposite direction if desired.

In the space between the tube sheet 10 and the adjacent fin 13 is acorrugated sheet 26 which rests on'the tubes 28 and supports closuremembers 30 and 32. A corrugated sheet 26 is similarly arranged betweentube sheet 12 and adjacent fin 13.

It is thus seen that fluid entering through opening .22 in manifold 18is conducted by manifold 18 to the space between adjacent fin 13 andtube sheet 10. The fluid then flows through hole 34 in fin 13 into thenext space from which it flows through circular holes 36 and triangularholes 38 of tin 14. The fluid then flows through the center hole 34 ofthe next fin 13. As clearly shown in Fig. .10, the. fluid continues toflow in this manner throughout the length of the heat exchanger and .isdischarged through manifolds 20 and the holes 24 therein.

Fins 13 and 14 have holes 40 and 42 respectively which receive tubes 28.Fins 13 have upwardly offset portions 44 and downwardly offset portions46. The height of portions 44 and 46 is such that they contact and arewelded to the next adjacent fins. The oflset portions therefore maintainuniform fin spacing, and they contribute to the strength and rigidity ofthe structure. The offset portions 44 and 46 also function asobstructions to direct the flow into intimate contact withthe tubes.

Inside of each tube 28 is corrugated fin 48 and an internal tube 50closed by a cap 52. In assembling the heat exchanger before brazing, thetubes 28 areassembled in the tube sheets 10 and 12 and in the fins 13and 14. The tubes 28 are then expandedas by forcing an expanding bullettherethrough, or by subjecting the tubes to fluid pressure.

When expanded, the tubes 28 hold the tube sheets 10 and 12 and the fins13 and 14 in assembled relationship. The fins 48 are then inserted inthe tubes 28 and the inner tube 50 is inserted internally of the fins48. The tube 50 is then expanded as by forcing an expanding bullettherethrough. After expansion of tube 50, fin 48 is in forced engagementwith tubes 28 and 50. After brazing, the fins 48 are brazed to the tubes28 and 50 and the caps 52 are brazed to the tubes 50.

In tube sheets 10 and 12, a groove 53 surrounds each fluid entrance andis adapted to receive an O-ring of neoprene or other flexible materialto seal the tubular passageways of the heat exchanger with respect tothe supply and discharge conduits, not shown. Threaded holes 54 in tubesheets 10 and 12 are adapted to receive screw members, not shown, whichhold the supply and discharge conduits in sealing engagement with thetube sheets 10 and 12 of the heat exchanger. Threaded studs 56 extendfrom the edges of tube sheets 10 and 12 and are adapted to secure supplyand dis-charge conduits, not shown, in communication with openings 22and 24 in manifolds 18 and 20.

We prefer to make the elements of this heat exchanger of aluminum. Thefins 13, 14, 26 and 48, and the closure members 16, 30 and 32 have ontheir contacting faces a brazing alloy which melts at a lowertemperature than the parent metal. It should be understood that, ifdesired, only one of two contacting surfaces need have the brazing alloycoating. Brazing rings and brazing foil are also mounted in or adjacentto other joints which are to be brazed. Brazing foil is used between thecontacting surfaces of manifolds 18 and 20, and members 10, 12, 16, 30and 32. The elements are held in assembled arrangement by a fixture. Thefixture and assembled elements are immersed in a salt bath containingsuitable flux at a temperature of approximately 1100 F. to melt thebrazing alloy and cause the elements to be brazed or welded into anintegral structure.

It should be understood that metals other than aluminum can be used. Itis only necessary to subject the assembly to the proper brazingtemperature for the metals 3 used and to carry outthe-brazing process inthe presence of a suitable flux or atmosphere.

While we have described the foregoing preferred embodiments of ourinvention, we contemplate that many changes may be made withoutdeparting from the scope or spirit of our invention, and we desire to belimited only by the claims.

' We claim:

1. A heat exchanger comprising spaced substantially flat and paralleltube sheets, a plurality of spaced fins between said tube sheets,'saidfins lying in planes substan tially parallel to said tube sheets,closure means extending along the peripheral edges of the fins to,enclose the spaces between the fins, a plurality of tubes extendingthrough said fins and into the openings in said tube sheets, said tubesbeing adapted to conduct a first heat exchange fluid, closure stripsbetween the tubesheets and the fins adjacent the tube sheets, saidclosure strips extending along all but a portion of the peripheral edgesof said adjacent fins to provide elongated openings, means supported bysaid tubes, said means engaging and supporting said closure strips atthe extremities of said elongated openings, manifolds secured to saidtube sheets and having passageways communicating with said elongatedopenings, said manifolds being adapted to receive and discharge a secondheat exchange fluid, said fins having openings therethrough for thepassage of said second heat exchange fluid from one tube sheet to theother.

2. A heat exchanger comprising spaced substantially flat tube sheets, aplurality of spaced fins between said tube sheets, said fins'lying inplanes substantially parallel to said tube sheets, closure meansextending along the peripheral edges of the fins to enclose the spacesbetween the fins and the spaces between the tube sheets and the fins,first tubes extending through said fins and into openings in said tubesheets, said first tubes being brazed to said fins, second tubes insideof said first tubes, corrugated fins in the spaces between the first andsecond tubes, means brazing said corrugated fins to said first andsecond tubes, means closing said second tubes to limit movement of afirst heat exchange fluid to the spaces between said first and secondtubes, a supply manifold secured to one of said tube sheets, said supplymanifold being adapted to be connected to a source of a second heatexchange fluid and having'a passageway communicating with the spacebetween said one tube sheet and the fin adjacent thereto, a dischargemanifold secured to the other of said tube sheets, said dischargemanifold having a passageway communicating with the space between theother of said tube sheets and the fin adjacent thereto, said fins havingopenings therethrough, the openings in alternate fins being ofiset fromthe openings in the other fins to cause said second heat exchange fluidto flow in a zigzag path from one tube sheet to the other tube sheet.

References Cited in the file of this patent UNITED STATES PATENTS

